The present disclosure relates to an image capturing device, an image capturing device control method, and a program, and more particularly, to an image capturing device, an image capturing device control method, and a program, in which a process of detecting and correcting deviation between a left eye image and a right eye image in an image capturing device (camera) capturing, for example, a 3-dimensional image (3D image), particularly, up and down image deviation is performed.
Recently, a display device such as a television and a PC capable of displaying a 3-dimensional image (3D image) and a video camera and a still image camera capable of recording a 3-dimensional image (3D image) have been developed and used. To display the 3D image, it is necessary to capture two images from different viewpoints. That is, two images are a left eye image from a left function point and a right eye image from a right function point.
When two images captured from different viewpoints are displayed, a control is performed such that the left eye image is viewed only by a left eye of a viewer and the right eye image is viewed only by a right eye of the viewer, and the viewer can obtain a 3-dimensional effect. As a display processing method of the 3D image, there are various methods.
For example, there is a method in which the left eye image and the right eye image are alternately displayed on the display device, the viewer puts on shutter type glasses, shutter conversion is performed for each of a display period of the left eye image and a display period of the right eye image, and each image is viewed only by one eye.
For example, there are various methods such as a method in which a left eye image and a right eye image are alternately displayed in a slit shape on a display device having a display face in which a lenticular lens is subjected to a special process, the left eye image is viewed through a lens of the display face only by a left eye of a viewer, the right eye image is viewed through a lens of the display face only by a right eye of the view, the 3-dimensional effect can be obtained by eyesight of the naked eyes.
To capture the 3D image, two image capturing units capturing the left eye image and the right eye image are separated at a proper distance and are horizontally disposed (left and right). Image deviation in the horizontal direction occurring between the left and right images is called parallax.
The parallax is recognized as depth information, and thus the viewer can 3-dimensiontally view the image.
The image deviation according to the positions of two image capturing units capturing the left eye image and the right eye image may occur in a direction other than the parallax direction in the horizontal direction.
For example, image deviation in the up and down direction as geometric deviation caused by various camera configurations, such as deviation in the up and down direction of axial disposition of two image capturing units, angular deviation in the up and down direction of the optical axes of two image capturing units, or positional deviation of an image capturing element from the optical axis.
The image deviation in the up and down direction between the left eye image and the right eye image in the 3D image is not only a case of interference in the 3-dimensional view but also a cause of fatigue of eyes of the viewer, and thus it is necessary to remove the deviation.
To correct the deviation in the up and down direction between the images, there is a method in which image comparison is performed by block matching or the like on two images captured by two image capturing units, conversion parameters for correcting the image deviation, for example, affine parameters are calculated, and conversion of the captured image is performed. Proper conversion parameters are input by an affine conversion circuit, conversion (affine conversion) of the captured image is performed, and thus it is possible to correct the geometric deviation between two pictures.
For example, Japanese Unexamined Patent Application Publication No. 2009-258868 (Sony Corporation) discloses a method of calculating affine parameters by block matching. In Japanese Unexamined Patent Application Publication No. 2009-258868, pictures with time difference are compared by one camera, but it may be applied to comparison of simultaneous pictures of two cameras.
Japanese Unexamined Patent Application Publication No. 2010-128820 (Fujifilm Corporation) discloses a method of estimating geometric conversion parameter when a plurality of cameras are used.
However, for example, the image comparison based on the block matching described in Japanese Unexamined Patent Application Publication No. 2010-128820 is performed to detect the image deviation, it is necessary to detect a sufficient number of characteristic points (correspondence points) in the image that is a comparison target.
For example, when most of a captured image is “void”, most of image areas of the left eye image and the right eye image captured by two image capturing units become images with uniform brightness with no change in brightness.
When the images with such uniform brightness are compared with each other, it is difficult to uniquely determine a block of the comparison target. Accordingly, it is difficult to detect effective characteristic points (correspondence points). As a result, detection precision in geometric deviation deteriorates. When correction is performed with low detection precision, it is difficult to sufficiently remove the geometric deviation, and there is a risk that the deviation is increased.